There are known fiber application machines, commonly known as fiber placement machines, for the application by contact on a layup tool, such as a male or female mold, of a wide band of several flat continuous fibers, ribbon-like, dry or impregnated with thermosetting or thermoplastic resin, in particular carbon fibers, consisting of a plurality of carbon filaments or threads.
These machines comprise a system for moving a fiber application head, said head comprising an application roller intended to come into contact against the mold to apply the band and means for guiding the fibers onto said application roller, the fiber storage means, and means for conveying fibers from said storage means to the application head.
In the patent document WO 2008122709, it was proposed to use conveying means comprising flexible tubes connecting the storage means to the application head, each flexible tube being able to receive a fiber in its internal passage. The flexible tubes are attached by their ends to the application head and to the storage means respectively by the upstream and downstream attachment means, and have sufficient length and flexibility as not to restrict the movements of the head displacement system. Each flexible tube is provided with at least one longitudinal flexible blade of rectangular cross-section, said flexible blade being arranged substantially parallel to the plane of transport of the fiber received in the internal passage of the flexible tube.
Such flexible tubes form conveying means that are simple in design, do not take up much space and are of reduced cost, making it possible to obtain high movement speeds, to place remotely the storage means from the displacement system, to eliminate the motor-driven slack recovery systems for fiber spools, to isolate the fibers from the outside, and to simplify the displacement system of the application head, particularly to use a displacement system such as a multi-articulated arm of the six-axis robot type.
The flexible blade associated with each tube restricts or prevents the transverse bending of the tube in the plane of the blade, which allows the risks of the fiber turning over in the internal passage of the flexible tube parallel to the blade to be eliminated, or at the very least restricted, especially when certain movements of the robot, due to excessive bending of the flexible tubes and/or excessive friction of the fibers in the flexible tubes. The flexible tube can perform bending movements in a direction perpendicular to the plane of the blade and twisting movements to allow the fiber placement head to move in all directions.
The assembly of the blade and the flexible tube is effected by means of an adhesive tape, the adhesive tape wound in a helical way around the tube and the blade to flatten it against the flexible tube. The set is covered by a protective sheath.
This assembly has proved to be long and fastidious to perform.
The purpose of the present invention is to provide a machine with conveying means ensuring a good fiber conveyance, which are simple to make.